Solutocapillary Effects of Sulphur in CaO-Al2O3 Slags, in Marangoni Instability and Convection Onset, Related to the Desulphurization of low Carbon, Aluminium Killed Steels
Journal Title: Analele Universitatii "Dunarea de Jos" din Galati. Fascicula IX, Metalurgie si Stiinta Materialelor - Year 2010, Vol 33, Issue 3
Abstract
Based on the “one layer model” applied to desulphurization slag layer with boundary conditions, imposed due to the sulphur transfer through the interface steel-slag during desulphurization process, the threshold conditions of instability for Marangoni convection in the desulphurization slag at 1873K are evaluated in the CaO-Al2O3 system at ratios CaO/Al2O3=1.5 and 1.0, for sulphur concentration lower than the solubility limit and in conditions of fully liquid slag. Threshold critical values ∆σc=(51−79.62)10-6 N/m, for the surface tension in slag and interfacial tension slag-steel, closed to the value ∆σcrit=30.748·10-6 N/m obtained in steel and Δ(S)crit =(20−44.73)10-4 mass%, for the local fluctuations of sulphur concentration , were found for onset instability and Marangoni convection in slag, at the minimal value of the critical dimensionless solutal number Mas c=80. There are small differences between numerical values of the quantities for threshold conditions obtained on the base of the surface tension of the slag and on the base of the interfacial tension steel-slag. The instability with onset of the turbulent convection is predicted to take place starting from values ∆σ>(312.36−501.61)·10-6 N/m, corresponding of Δ(S)=(126−228.82)·10-4mass%. An enhancement coefficient of the mass transfer of sulphur at interface on the slag side is established in the conditions of the onset Marangoni flow and convection. The solutal parameter Δ(S) is the most sensitive in contributing to instability conditions and in producing mixing effects in slag in a thickness layer δeff at interface, by energy dissipation of Marangoni flow and helps to make important differences between conditions in slags C/A=1.5 and C/A=1.
Authors and Affiliations
Petre Stelian NITA
Keywords
Related Articles
- EP ID EP630584
- DOI -
- Views 85
- Downloads 0
Versatility of Nickel-Aluminium Bronzes as Wear Resisting Materials
The paper presents the results of experimental research regarding the establishing of some chemical positions of the nickel-aluminium bronzes used as monoblock and bimetallic bearings. The areas of the applications are...
Photocatalytical Activities of Manganese Doped Zinc Oxide Nanoparticles Prepared by Sol-Gel Method
In the last period, ZnO and doped ZnO nanoparticles are intensively investigated for their photocatalytic properties. This paper reports on ZnO and Mndoped ZnO nanoparticles obtained by modified ol-gel method. Were stud...
Software Used at Castings Production
The foundry industry has been developed worldwide, a number of software that can assist the design work and various processes in the production of castings. Current usage of such software by metallurgical engineers is po...
Choosing and Using Rationally the Thermic Processed Steels
On a global scale one can notice a constant preoccupation for a rational choosing and using of the materials on the whole and, especially of the steels with the main objective the increase of the machines’, equipment’ an...
Magnetical Properties of Silicon Steels Used for Electrotechnical Industries
This paper-work shows the laboratory experiments achieved on more silicon steel plates, where the magnetic ranges were spot- lighted by particular technical requirements. On the same plates the texture analyses were made...